In general, an image encoder conducts image encoding on image data composed of a plurality of pixels. In conventional image encoding processing, a plurality of pixels are input in the order of raster scan and image encoding processing is conducted on the input pixels by using a pixel adjacent to one side of each of the input pixels in image data as a reference pixel.
In the conventional image encoding processing, however, there is a depending relation between the input pixel and the reference pixel (that is, image encoding on the input pixel depends upon the reference pixel). Therefore, it is difficult to implement to conduct a plurality of kinds of image encoding processing in parallel and in a pipeline form. As a result, there is a problem that the throughput of image encoding processing is lowered.